FF13:
-The Eidolon battles. I mean really. In what universe is it considered good game design to have the difficulty spike THAT MUCH from normal gameplay.

it was so bad it broke the game for me. still have yet to make it past the horse one. OT in other games id say sephiroth in KH/KH2 but then again thats because his the only boss thats actually meant to be hard in those games. Zeus at the end of GOW 2 seeing as i wail on the fucker for days and it doesn't seem to do a damn thing then he zaps me once and I'm fucked.

Final Fantasy XIII-2, I believe it's a boss fight in Oerba, where you fight Caius ontop of the schoolhouse or something. Killed EVERYTHING I came accross in every timeline up until that point (not including the huge plains area, screw that), and it still seemed I needed to grind another 2 hours or so. That game was challenging. But, TBH, I quit after attempting that fight 10-12 times.

By Blizzard Entertainment:
Part of the reason is that Battlegrounds are like ducks.

Gears of war 1, hardcore, single player mode, general raam..... R.i.p 3x Xbox controllers.....

Raam is a bitch but if you have the right strategy he's not so bad. There's a Torque Bow hidden on the right side of the room just before him. Torque Bows have the highest damage of any weapon in the game and they have the added benefit of being explosive. Arm yourself with a Torque Bow, a Lancer and max grenades. Don't fall for the noob trap of using the Sniper.

When the fight starts, just unload on him with active Torque shots as fast as possible. If you hit him all 6 times, 5 of them being actives, you can easily take off half his HP on Insane. Then just carefully pick at him with the Lancer when his Krill are in the air. Remember that you can shoot the Krill before they reach you, thus making it so you don't have to take cover against them. Continue doing this until Raam gets close to your cover and starts moving to the left or right. When he does this, switch to your grenades and blind throw all 4 of them. If you're careful, you can bounce them off one of the low walls that's just past Raam so that they land at his feet.

And that should be the end of it, even on insane. As long as you get a good phase 1 he should be low enough health that the grenades kill him. The trick to making this fight easy when solo is to one phase him. This may take a couple of tries, because in addition to player skill being a big factor, there's also several RNG elements to this fight. If he downs Dom early on, or forces you into cover by shooting a lot, you may not get enough damage on him for the grenades to finish him. If that happens, you can try running to the other side of the train, but it's about 50/50 on if you'll make it there alive, since his turret feels like it 2 shots you on insane. There's also the random Reavers that fly by and shoot at you. They're usually pretty inaccurate, but if you get unlucky they can kill you, even in cover. You can also just get unlucky with the timing of your shots because if they happen to shoot you when you're up you can take extreme burst damage from them + Raam.

If things go your way though and you try to one phase him, he's not too bad.

If Goku's power level increases at the same rate till the end of DBGT as it does till the end of the Frieza saga, as a SS4 Goku would have a PL of roughly 939 Quinoctogintillion. For reference that is a 260 digit number. A PL of 14,600 is required to destroy an earth sized planet. There are about 2 nonillion earths worth of mass in the universe. That means SS4 Goku can destroy the universe about 32 Octosexagintillion times over. There's a reason they made Goku a god at the end of GT.

I found Jetstream Sam on hardest to be quite annoying but still satisfying as hell to fight because of the bad ass music that plays during the fight and the fact that it's a 1 vs 1 showdown with swords
This song in a boss fight just screams epic

A wise man once said: "Does it matter what religion you are?
we﻿ are here to connect each other people in the world ... through MUSIC"

Being underleveled and fighting Xigbar from Kingdom hearts 2. I've fought and defeated sephiroth in both games and nothing came close to being as hard as Xigbar.
But it was probably also one of the finest moments when gaming after I defeated him, because everything was planned out to the end and I spent soo many hours

I wont say any WoW bosses that might have taken it, because I was only in one guild where I did not out right out class everyone there (Large time constraints until I started college). But I think that Ice dragon boss in ICC would take it. (due to guild It took me more trys then firefighter..)

But in terms of really annoying and hard due to me sucking FF8 last boss. I had no idea how to play games back then and it took me 100's of try's. Until I found a way to spam the most powerful attack in the game every turn kill each phase in 3-4 turns compare to the 50 or so they're meant to take.

Probably anything from Ys: Oath in Felghana. I'm pretty sure a sadist designed every single boss in that game. :x

Someone else who knows about this game, I never thought I'd see the day.

I totally have to agree with you. Some bosses weren't that hard, but took forever to kill and if you got hit just once it was pretty much game over. Other bosses were just downright difficult and caused me to spend many long hours trying to get them down, all to no avail.

Was a great game, certainly worth every single cent I spent, but good lord those bosses were unforgiving.

Last boss in Sonic Adventure 2 (or second last). You have to kill some gigantic beast that spews a shitton of orbs you have to avoid which during you have to get up the beasts back to attack him. I still haven't managed beating him